Ultrasonic fluid measuring device

ABSTRACT

An ultrasonic fluid measuring device capable of improving a measuring accuracy is provided. An ultrasonic fluid measuring device  10  includes an ultrasonic measuring portion  20  in which a first ultrasonic transmitter-receiver  21  and a second ultrasonic transmitter-receiver  22  are provided to a measuring pass  14 , and first to fifth pass partition plates  25  to  29  that are set in substantially parallel with an ultrasonic propagation path  24  that connects the first ultrasonic transmitter-receiver  21  and the second ultrasonic transmitter-receiver  22 , whereby first to sixth flat passes  32  to  37  are laminated/formed in the measuring pass  14  by the pass partition plates  25  to  29 . In this ultrasonic fluid measuring device  10 , the first ultrasonic transmitter-receiver  21  and the second ultrasonic transmitter-receiver  22  are arranged with respect to respective flat passes  32  to  37  such that the ultrasonic measuring portion  20  measures a flow rate of the flat pass that is deviated from a center along a lamination direction.

TECHNICAL FIELD

The present invention relates to an ultrasonic fluid measuring deviceconstructed such that a first ultrasonic transmitter-receiver and asecond ultrasonic transmitter-receiver of an ultrasonic measuringportion are provided to a measuring pass so as to measure a flow rate ofa fluid flowing through the measuring pass by the ultrasonic measuringportion.

BACKGROUND ART

The ultrasonic fluid measuring device is the device that measures apropagation time of an ultrasonic wave in such a situation that theultrasonic wave is caused to propagate through a measuring pass whileflowing a fluid through the measuring pass, and then detects a flow rateof the fluid based on measured information.

A pair of ultrasonic transmitter-receivers are provided to the sidesurfaces of the short sides, which oppose to each other like a squarecylinder shape whose cross section is a rectangle, of the measuring passrespectively.

These paired ultrasonic transmitter-receivers are arranged along a line,which intersect with the flowing direction of the measuring pass at apredetermined angle, to transmit/receive the ultrasonic wave.

Also, recently the ultrasonic fluid measuring device whose measuringpass is constructed as a multi-layered pass by arranging a plurality ofpartition plates in parallel in the measuring pass to improve ameasuring accuracy has been proposed (see Patent Literature 1, forexample). Patent Literature 1: WO2004/074783

DISCLOSURE OF THE INVENTION Problems that the Invention is to Solve

However, when the measuring pass is constructed as the multi-layeredpass, for example, a flow rate has a maximum value in the pass in acenter layer of multiple layers whereas a flow rate is decreased as alocation becomes more distant from the center layer.

In this manner, since the fluid flowing through the multi-layered passhas a different flow rate every layered pass, there existed a problem inenhancing a measuring accuracy of an average flow rate of the fluid thatflows through the measuring pass.

The present invention aims at providing an ultrasonic fluid measuringdevice capable of improving a measuring accuracy of an average flowrate.

Means for Solving the Problems

An ultrasonic fluid measuring device of the present invention, includesa measuring pass formed like a square cylinder whose cross section is arectangle; an ultrasonic measuring portion in which a first ultrasonictransmitter-receiver and a second ultrasonic transmitter-receiver areprovided to the measuring pass; and a plurality of pass partition platescontained in the measuring pass such that the pass partition plates areset in substantially parallel with an ultrasonic propagation path thatconnects the first ultrasonic transmitter-receiver and the secondultrasonic transmitter-receiver; whereby a plurality of flat passes arelaminated/formed in the measuring pass by the pass partition plates, andwherein the first ultrasonic transmitter-receiver and the secondultrasonic transmitter-receiver are arranged with respect to respectiveflat passes such that the ultrasonic measuring portion measures a flowrate of the flat pass that is deviated from a center along a laminationdirection.

Here, a flow rate in the flat pass located near the center along thelamination direction tends to have a highest value. Therefore, the firstultrasonic transmitter-receiver and the second ultrasonictransmitter-receiver are arranged such that the ultrasonic measuringportion measures a flow rate of the flat pass that is deviated from thecenter along the lamination direction out of a plurality of flat passes.

Since a flow rate of the flat pass except the flat passes that arelocated near the center to exhibit a highest flow rate is measured, avalue close to an average flow rate can be measured.

Also, in the ultrasonic fluid measuring device of the present invention,the first ultrasonic transmitter-receiver and the second ultrasonictransmitter-receiver are arranged to face to the flat pass that flowsthe fluid at an average flow rate out of the flat passes.

The first ultrasonic transmitter-receiver and the second ultrasonictransmitter-receiver are arranged to face to the flat pass that flowsthe fluid at an average flow rate out of a plurality of flat passes.Therefore, an average flow rate can be measured by the first ultrasonictransmitter-receiver and the second ultrasonic transmitter-receiver.

Also, in the ultrasonic fluid measuring device of the present invention,the first ultrasonic transmitter-receiver and the second ultrasonictransmitter-receiver are arranged to extend over a plurality of flatpasses that are adjacent mutually out of the flat passes.

The first ultrasonic transmitter-receiver and the second ultrasonictransmitter-receiver are arranged to extend over a plurality of flatpasses that are adjacent mutually, out of the flat passes except theflat passes that are located near the center to exhibit a highest flowrate.

Since a flow rate of the fluid passing through a plurality of flatpasses is measured, a value close to an average flow rate can bemeasured.

Also, in the ultrasonic fluid measuring device of the present invention,the first ultrasonic transmitter-receiver and the second ultrasonictransmitter-receiver are arranged to face to the flat passes excepteither of the flat passes, through which the fluid passes at a highestflow rate, and the flat passes, through which the fluid passes at alowest flow rate.

The first ultrasonic transmitter-receiver and the second ultrasonictransmitter-receiver are arranged to face to the flat passes excepteither of the flat passes, through which the fluid passes at a highestflow rate, and the flat passes, through which the fluid passes at alowest flow rate, out of the flat passes apart from the flat passes thatare located near the center to exhibit a highest flow rate. Therefore, avalue close to an average flow rate can be measured by the firstultrasonic transmitter-receiver and the second ultrasonictransmitter-receiver.

Also, an ultrasonic fluid measuring device of the present invention,includes a measuring pass formed like a square cylinder whose crosssection is a rectangle; an ultrasonic measuring portion in which a firstultrasonic transmitter-receiver and a second ultrasonictransmitter-receiver are provided to the measuring pass; and a pluralityof pass partition plates contained in the measuring pass such that thepass partition plates are set in substantially parallel with anultrasonic propagation path that connects the first ultrasonictransmitter-receiver and the second ultrasonic transmitter-receiver;whereby a plurality of flat passes are laminated/formed in the measuringpass by the pass partition plates, and wherein the first ultrasonictransmitter-receiver and the second ultrasonic transmitter-receiver arearranged to face to the flat passes except either of the flat passes,through which the fluid passes at a highest flow rate, and the flatpasses, through which the fluid passes at a lowest flow rate.

The first ultrasonic transmitter-receiver and the second ultrasonictransmitter-receiver are arranged to face to the flat passes excepteither of the flat passes, through which the fluid passes at a highestflow rate, and the flat passes, through which the fluid passes at alowest flow rate. Therefore, a value close to an average flow rate canbe measured by the first ultrasonic transmitter-receiver and the secondultrasonic transmitter-receiver.

Also, in the ultrasonic fluid measuring device of the present invention,the ultrasonic propagation path that connects the first ultrasonictransmitter-receiver and the second ultrasonic transmitter-receiver hasan angle to a flow of the measuring pass.

Also, in the ultrasonic fluid measuring device of the present invention,the first ultrasonic transmitter-receiver and the second ultrasonictransmitter-receiver are provided to a side wall on a same side of themeasuring pass, and a propagation time of an ultrasonic wave is measuredby causing an ultrasonic wave to reflect on an opposing side wallsurface of the measuring pass.

Also, in the ultrasonic fluid measuring device of the present invention,the ultrasonic propagation path that connects the first ultrasonictransmitter-receiver and the second ultrasonic transmitter-receiver isset in substantially parallel with a flow in the measuring pass.

Also, the ultrasonic fluid measuring device of the present invention,further includes a first ultrasonic measuring portion and a secondultrasonic measuring portion; wherein the first ultrasonictransmitter-receiver and the second ultrasonic transmitter-receiver ofthe first ultrasonic measuring portion are arranged such that the firstultrasonic measuring portion measures a flow rate of one flat pass thatis deviated from a center along a lamination direction out of the flatpasses, and the first ultrasonic transmitter-receiver and the secondultrasonic transmitter-receiver of the second ultrasonic measuringportion are arranged such that the second ultrasonic measuring portionmeasures a flow rate of other flat pass that is deviated from the centeralong the lamination direction.

Also, in the ultrasonic fluid measuring device of the present invention,a first ultrasonic propagation path of the first ultrasonic measuringportion and a second ultrasonic propagation path of the secondultrasonic measuring portion are set in parallel when viewed along thelamination direction.

Also, in the ultrasonic fluid measuring device of the present invention,a first ultrasonic propagation path of the first ultrasonic measuringportion and a second ultrasonic propagation path of the secondultrasonic measuring portion intersect with each other when viewed alongthe lamination direction.

ADVANTAGES OF THE INVENTION

According to the ultrasonic fluid measuring device of the presentinvention, a value close to an average flow rate can be measured by thefirst ultrasonic transmitter-receiver and the second ultrasonictransmitter-receiver, and therefore such an advantage is obtained that ameasuring accuracy can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing an ultrasonic fluid measuring device(first embodiment) according to the present invention.

FIG. 2 is a perspective view showing an ultrasonic measuring portion ofthe ultrasonic fluid measuring device according to the first embodimentof the present invention.

FIG. 3 is a sectional view taken along an A-A line in FIG. 1.

FIG. 4 is an enlarged view showing the ultrasonic measuring portionaccording to the first embodiment.

FIG. 5 is an enlarged view showing an ultrasonic measuring portion of anultrasonic fluid measuring device according to a second embodiment.

FIG. 6 is an enlarged view showing an ultrasonic measuring portion of anultrasonic fluid measuring device according to a third embodiment.

FIG. 7 is an enlarged view showing an ultrasonic measuring portion of anultrasonic fluid measuring device according to a fourth embodiment.

FIGS. 8A and 8B are an enlarged view and a major schematic perspectiveview showing an ultrasonic measuring portion of an ultrasonic fluidmeasuring device according to a fifth embodiment.

FIGS. 9A to 9C are an enlarged view, a major schematic perspective view,and a major schematic plan view showing an ultrasonic measuring portionof an ultrasonic fluid measuring device according to a sixth embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Description ofReference Numerals and Signs

-   -   10, 50, 60, 70, 80, 90 ultrasonic fluid measuring device    -   14 measuring pass    -   15, 16 left and right side walls (a pair of opposing inner        surfaces)    -   20, 20A, 20B ultrasonic measuring portion    -   21, 51, 51A, 51B, 61, 71 first ultrasonic transmitter-receiver    -   22, 52, 52A, 52B, 62, 72 second ultrasonic transmitter-receiver    -   24, 24A, 24B ultrasonic propagation path    -   25 to 29 first to fifth pass partition plates (a plurality of        pass partition plates)    -   32 to 37 first to sixth flat passes (a plurality of flat passes)    -   38 fluid    -   39 center along the lamination direction

BEST MODE FOR CARRYING OUT THE INVENTION

Respective ultrasonic fluid measuring devices according to embodimentsof the present invention will be explained with reference to thedrawings hereinafter.

First Embodiment

As shown in FIG. 1 to FIG. 3, an ultrasonic fluid measuring device 10according to a first embodiment of the present invention includes afluid pass 11, an ultrasonic measuring portion 20, and first to fifthpass partition plates 25 to 29 as a plurality of pass partition plates.The fluid pass 11 is formed into an almost U-shape by left and rightvertical passes 12, 13 and a horizontal pass (measuring pass) 14. In theultrasonic measuring portion 20, a first ultrasonic transmitter-receiver(ultrasonic transmitter) 21 and a second ultrasonic transmitter-receiver(ultrasonic receiver) 22 are provided to left and right side walls (apair of opposing inner surfaces) 15, 16 in the measuring pass 14respectively. The first to fifth pass partition plates 25 to 29 arecontained in the measuring pass 14 such that these pass partition platesare arranged in substantially parallel with an ultrasonic propagationpath 24 that is provided to connect the first ultrasonictransmitter-receiver 21 and the second ultrasonic transmitter-receiver22 when viewed from the side.

The ultrasonic propagation path 24 is arranged to face to the flow at anangle. In this case, such an arrangement pattern is called the Z-path orthe Z method that the first and second ultrasonic transmitter-receivers21, 22 are arranged to face to the flow at an angle. In the presentembodiment, explanation will be made based on this Z path arrangement.

The fluid pass 11 has an isolation valve 31 on the left vertical pass12. First to fifth pass partition plates 25 to 29 are provided at aconstant interval in the measuring pass 14 along upper and lower wallportions 17, 18.

As shown in FIG. 2, the measuring pass 14 is shaped into a squarecylinder whose cross section is a rectangle, by left and right sidewalls 15, 16 and the upper and lower wall portions 17, 18. Also, sincethe first to fifth pass partition plates 25 to 29 are provided at aconstant interval in the measuring pass 14, first to sixth flat passes32 to 37 are laminated/formed as a plurality of flat passes in themeasuring pass 14, as shown in FIG. 4.

The first to sixth flat passes 32 to 37 are formed to have a crosssection of an almost rectangular shape respectively.

In the fluid pass 11, as shown in FIG. 4, when the isolation valve 31 isopened from a close position indicated by a chain double-dashed line toan open position indicated by a solid line, a fluid (for example, a gas)38 flows from the left vertical pass 12 to the right vertical pass 13through the measuring pass 14, as indicated with an arrow.

At this time, as shown in FIG. 4, out of the first to sixth flat passes32 to 37, the fluid 38 that flows through the third and fourth flatpasses 34 to 35 located near a fluid pass center (center) 39 of themeasuring pass 14 has a maximum flow rate.

Also, it is highly possible that, out of the first to sixth flat passes32 to 37, the fluid 38 in the first and sixth flat passes 32, 37 locatednear the upper and lower wall portions 17, 18 of the measuring pass 14has a minimum flow rate.

Also, it is highly possible that, out of the first to sixth flat passes32 to 37, the fluid 38 in the second and fifth flat passes 33, 36 has anaverage flow rate.

In the ultrasonic measuring portion 20, the first ultrasonictransmitter-receiver 21 and the second ultrasonic transmitter-receiver22 are arranged to deviate downward from the center 39 along thelamination direction (i.e., in the vertical direction) by a height(distance) H with respect to the first to sixth flat passes 32 to 37.Then, a calculating portion 41 is connected to the first ultrasonictransmitter-receiver 21 and the second ultrasonic transmitter-receiver22.

When the first ultrasonic transmitter-receiver 21 and the secondultrasonic transmitter-receiver 22 are arranged to deviate downward fromthe center 39 by a height H, the first ultrasonic transmitter-receiver21 and the second ultrasonic transmitter-receiver 22 can be arranged toface to the fifth flat pass 36 by way of example.

In a situation that the first ultrasonic transmitter-receiver 21 and thesecond ultrasonic transmitter-receiver 22 are arranged to face to thefifth flat pass 36, the ultrasonic measuring portion 20 can measure aflow rate in the fifth flat pass 36 through which the fluid 38 passes atan average flow rate.

The first ultrasonic transmitter-receiver 21 is arranged on a portion15A, which faces to the fifth flat pass 36 and is located on theupstream side of the second ultrasonic transmitter-receiver 22, of theleft side wall 15 via an ultrasonic transmitting material 21A (see FIG.3).

The second ultrasonic transmitter-receiver 22 is arranged on a portion16A, which faces to the fifth flat pass 36 and is located on thedownstream side of the first ultrasonic transmitter-receiver 21, of theright side wall 16 via an ultrasonic transmitting material 22A (see FIG.3).

Concretely, as shown in FIG. 3, the ultrasonic propagation path 24between the first ultrasonic transmitter-receiver 21 and the secondultrasonic transmitter-receiver 22 is the Z-path that is set at an angleθ to the flow direction (the direction indicated with an arrow) of thefifth flat pass 36 to cross obliquely the flow direction of the fifthflat pass 36 when viewed from the top.

Also, a propagation distance of the ultrasonic propagation path 24between the first ultrasonic transmitter-receiver 21 and the secondultrasonic transmitter-receiver 22 is set to L.

Based on respective data of a sound velocity C, the propagation distanceL, an angle θ of the ultrasonic propagation path, a first ultrasonicpropagation time T1 required of the ultrasonic wave to travel from thefirst ultrasonic transmitter-receiver 21 to the second ultrasonictransmitter-receiver 22, and a second ultrasonic propagation time T2required of the ultrasonic wave to travel from the second ultrasonictransmitter-receiver 22 to the first ultrasonic transmitter-receiver 21,the calculating portion 41 calculates a flow rate U of the fluid by Eq.(1) to Eq. (3).

T1=L/(C+U cos θ)  (1)

T2=L/(C−U cos θ)  (2)

U=L/2 cos θ((1/T1)−(1/T2))  (3)

Next, an operation of the ultrasonic fluid measuring device 10 accordingto the first embodiment will be explained with reference to FIG. 1, FIG.3, and FIG. 4 hereunder.

The fluid (gas) 38 is caused to flow into the left vertical pass 12 byopening the isolation valve 31 of the fluid pass 11 shown in FIG. 1. Thefluid 38 that flows into the left vertical pass 12 flows in turn intothe measuring pass 14. The fluid 38 that flows into the measuring pass14 flows in turn into the first to sixth flat passes 32 to 37 shown inFIG. 4.

As shown in FIG. 4, there is a high possibility that, out of the firstto sixth flat passes 32 to 37, the fluid 38 in the second and fifth flatpasses 33, 36 has an average flow rate.

The ultrasonic wave is emitted toward the second ultrasonictransmitter-receiver 22 from the first ultrasonic transmitter-receiver21 shown in FIG. 4. The ultrasonic wave is propagated from the firstultrasonic transmitter-receiver 21 to the second ultrasonictransmitter-receiver 22 through the fluid 38 in the fifth flat pass 36.The first ultrasonic propagation time T1 needed when the ultrasonic waveis propagated from the first ultrasonic transmitter-receiver 21 to thesecond ultrasonic transmitter-receiver 22 is calculated by thecalculating portion 41.

Similarly, the ultrasonic wave is emitted toward the first ultrasonictransmitter-receiver 21 from the second ultrasonic transmitter-receiver22. The ultrasonic wave is propagated from the second ultrasonictransmitter-receiver 22 to the first ultrasonic transmitter-receiver 21through the fluid 38 in the fifth flat pass 36. The second ultrasonicpropagation time T2 needed when the ultrasonic wave is propagated fromthe second ultrasonic transmitter-receiver 22 to the first ultrasonictransmitter-receiver 21 is calculated by the calculating portion 41.

The flow rate U of the gas is calculated based on the first and secondultrasonic propagation times T1, T2.

Here, it is highly possible that the fluid 38 in the fifth flat pass 36out of the first to sixth flat passes 32 to 37 has an average flow rate.

Therefore, when a flow rate of the fluid 38 flowing through the fifthflat pass 36 is measured, an average flow rate of the fluid 38 can bemeasured. As a result, a flow rate of the fluid 38 can be measured withgood accuracy.

In the present embodiment, the fluid pass 11 is formed into an almostU-shape by the left and right vertical passes 12, 13 and the horizontalpass (measuring pass) 14. But any fluid pass may be employed if suchfluid pass may be formed into a U-shape, and the fluid pass is notrestricted to this embodiment. For example, a configuration obtained byturning the present embodiment by 90 degree may be employed, i.e., afluid pass may be constructed by upper and lower vertical passes and avertical pass (measuring pass).

Next, ultrasonic fluid measuring devices according to second to fourthembodiments will be explained with reference to FIG. 5 to FIG. 7hereunder. In order to facilitate the understanding of the ultrasonicfluid measuring device, the ultrasonic transmitting materials 21A, 22Aare omitted from FIG. 5 to FIG. 7.

Second Embodiment

In an ultrasonic fluid measuring device 50 shown in FIG. 5 according toa second embodiment, a first ultrasonic transmitter-receiver 51 and asecond ultrasonic transmitter-receiver 52 are arranged to deviatedownward from the center 39 along the lamination direction (i.e., in thevertical direction) by a height (distance) H and extend over themutually neighboring third to sixth flat passes 34 to 37, for example,out of the first to sixth flat passes 32 to 37. Remaining configurationsare similar to those in the first embodiment.

The first ultrasonic transmitter-receiver 51 has the same functions asthe first ultrasonic transmitter-receiver 21 except that its shape isenlarged in size in contrast to the first ultrasonictransmitter-receiver 21 of the first embodiment.

The second ultrasonic transmitter-receiver 52 has the same functions asthe second ultrasonic transmitter-receiver 22 except that its shape isenlarged in size in contrast to the second ultrasonictransmitter-receiver 22 of the first embodiment.

According to the ultrasonic fluid measuring device 50 of the secondembodiment, the first ultrasonic transmitter-receiver 51 and the secondultrasonic transmitter-receiver 52 are arranged to extend over themutually neighboring third to sixth flat passes 34 to 37, and thereforea flow rate of the fluid 38 passing through the third to sixth flatpasses 34 to 37 can be measured. As a result, a value close to anaverage flow rate can be measured.

Third Embodiment

In an ultrasonic fluid measuring device 60 shown in FIG. 6 according toa third embodiment, a first ultrasonic transmitter-receiver 61 and asecond ultrasonic transmitter-receiver 62 are arranged to deviatedownward from the center 39 along the lamination direction (i.e., in thevertical direction) by a height (distance) H and face to the fifth andsixth flat passes 36, 37, for example, as the flat passes out of thefirst to sixth flat passes 32 to 37 except either of the third andfourth flat passes 34, 35, through which the fluid 38 passes at ahighest flow rate, and the first and sixth flat passes 32, 37, throughwhich the fluid 38 passes at a lowest flow rate. Remainingconfigurations are similar to those in the first embodiment.

The first ultrasonic transmitter-receiver 61 has the same functions asthe first ultrasonic transmitter-receiver 21 except that its shape isenlarged in size in contrast to the first ultrasonictransmitter-receiver 21 of the first embodiment.

The second ultrasonic transmitter-receiver 62 has the same functions asthe second ultrasonic transmitter-receiver 22 except that its shape isenlarged in size in contrast to the second ultrasonictransmitter-receiver 22 of the first embodiment.

According to the ultrasonic fluid measuring device 60 of the thirdembodiment, the first ultrasonic transmitter-receiver 61 and the secondultrasonic transmitter-receiver 62 are arranged to face to the fifth andsixth flat passes 36, 37 except either of the third and fourth flatpasses 34, 35 that give the highest flow rate and the first and sixthflat passes 32, 37 that give the lowest flow rate, out of all flatpasses apart from the flat passes located near the center (third andfourth flat passes 34, 35). As a result, a value close to an averageflow rate can be measured by the first ultrasonic transmitter-receiver61 and the second ultrasonic transmitter-receiver 62.

Fourth Embodiment

In an ultrasonic fluid measuring device 70 shown in FIG. 7 according toa fourth embodiment, a first ultrasonic transmitter-receiver 71 and asecond ultrasonic transmitter-receiver 72 are arranged to face to thethird to fifth flat passes 34 to 36, for example, as the flat passes outof the first to sixth flat passes 32 to 37 except either of the thirdand fourth flat passes 34, 35, through which the fluid 38 passes at ahighest flow rate, and the first and sixth flat passes 32, 37, throughwhich the fluid 38 passes at a lowest flow rate. Remainingconfigurations are similar to those in the first embodiment.

The first ultrasonic transmitter-receiver 71 has the same functions asthe first ultrasonic transmitter-receiver 21 except that its shape isenlarged in size in contrast to the first ultrasonictransmitter-receiver 21 of the first embodiment.

The second ultrasonic transmitter-receiver 72 has the same functions asthe second ultrasonic transmitter-receiver 22 except that its shape isenlarged in size in contrast to the second ultrasonictransmitter-receiver 22 of the first embodiment.

According to the ultrasonic fluid measuring device 70 of the fourthembodiment, the first ultrasonic transmitter-receiver 71 and the secondultrasonic transmitter-receiver 72 are arranged to face to the third tofifth flat passes 34 to 36 except either of the third and fourth flatpasses 34, 35 that give the highest flow rate and the first and sixthflat passes 32, 37 that give the lowest flow rate. As a result, a valueclose to an average flow rate can be measured by the first ultrasonictransmitter-receiver 71 and the second ultrasonic transmitter-receiver72.

In the above embodiment, an example in which the ultrasonic propagationpath 24 between the first ultrasonic transmitter-receiver 21 and thesecond ultrasonic transmitter-receiver 22 is set to correspond to theZ-path is explained. The present invention is not restricted to thisembodiment. As the ultrasonic propagation path 24, a pair of ultrasonictransmitter-receivers 21, 22 may be provided to the side wall 15 or theside wall 16 on the same side of the measuring pass 14, and then thepropagation time of the ultrasonic wave may be measured by causing theultrasonic wave to reflect on the opposing side wall surface of themeasuring pass 14 once (the V-path or the V method) or twice (the W-pathor the W method). Also, such an ultrasonic transmitter-receiverarranging pattern (the I-path or the I method) may be employed that apair of ultrasonic transmitter-receivers 21, 22 are provided with noangle to the flow, i.e., the ultrasonic wave is transmitted/received inparallel with the flow.

Also, the shapes and the configurations of the fluid pass 11, themeasuring pass 14, and the like illustrated in the above embodiment arenot restricted to them, and may be changed appropriately.

For example, a fifth embodiment shown in FIGS. 8A and 8B and a sixthembodiment shown in FIGS. 9A to 9C are also contained in the presentinvention.

An ultrasonic fluid measuring device 80 shown in FIGS. 8A and 8Baccording to a fifth embodiment is equipped with a first ultrasonicmeasuring portion 20A and a second ultrasonic measuring portion 20B. Thefirst ultrasonic measuring portion 20A and the second ultrasonicmeasuring portion 20B are arranged in positions that are deviate upwardand downward from the center 39 along the lamination direction (i.e., inthe vertical direction) out of the first to sixth flat passes 32 to 37.

Concretely, a first ultrasonic transmitter-receiver 51A and a secondultrasonic transmitter-receiver 52A are arranged in the first ultrasonicmeasuring portion 20A to extend over the mutually neighboring the firstto third flat passes 32 to 34.

In contrast, a first ultrasonic transmitter-receiver 51B and a secondultrasonic transmitter-receiver 52B are arranged in the secondultrasonic measuring portion 20B to extend over the mutually neighboringthe fourth to sixth flat passes 35 to 37.

Therefore, as shown in FIG. 8B, in the ultrasonic fluid measuring device80, an ultrasonic propagation path 24A between the first ultrasonictransmitter-receiver 51A and the second ultrasonic transmitter-receiver52A and an ultrasonic propagation path 24B between the first ultrasonictransmitter-receiver 51B and the second ultrasonic transmitter-receiver52B are set in parallel with each other when views along the laminationdirection of the first to sixth flat passes 32 to 37.

According to this ultrasonic fluid measuring device 80, when the flowsin all the first to sixth flat passes 32 to 37 are measured by the firstultrasonic measuring portion 20A and the second ultrasonic measuringportion 20B, a flow rate of the fluid 38 can be measured further withgood accuracy.

Also, normally a flow rate of the fluid 38 is measured by using only oneof the first ultrasonic measuring portion 20A and the second ultrasonicmeasuring portion 20B. When a high accuracy measurement is needed, aflow rate of the fluid 38 can be measured further with good accuracy byusing both the first ultrasonic measuring portion 20A and the secondultrasonic measuring portion 20B.

An ultrasonic fluid measuring device 90 shown in FIGS. 9A to 9Caccording to a sixth embodiment is a variation of the above fifthembodiment. The first ultrasonic transmitter-receiver 51A, the secondultrasonic transmitter-receiver 52A, the first ultrasonictransmitter-receiver 51B, and the second ultrasonic transmitter-receiver52B are arranged such that the ultrasonic propagation path 24A and theultrasonic propagation path 24B intersect with each other when viewedalong the lamination direction of the first to sixth flat passes 32 to37 (see FIGS. 9B,9C).

According to the ultrasonic fluid measuring device 90, like the abovefifth embodiment, when the flows in all the first to sixth flat passes32 to 37 are measured by the first ultrasonic measuring portion 20A andthe second ultrasonic measuring portion 20B, a flow rate of the fluid 38can be measured further with good accuracy.

Also, normally a flow rate of the fluid 38 is measured by using only oneof the first ultrasonic measuring portion 20A and the second ultrasonicmeasuring portion 20B. When a high accuracy measurement is needed, aflow rate of the fluid 38 can be measured further with good accuracy byusing both the first ultrasonic measuring portion 20A and the secondultrasonic measuring portion 20B.

Also, when one ultrasonic measuring portion, which is suitable for aflow rate of the fluid 38, out of the first ultrasonic measuring portion20A and the second ultrasonic measuring portion 20B is used selectively,an optimum measured value responding to a flow rate of the fluid 38 canbe obtained. Thus, a measuring accuracy can be improved.

This application is based upon Japanese Patent Application (PatentApplication No. 2006-254432) filed on Sep. 20, 2006; the contents ofwhich are incorporated herein by reference.

The present invention is suitable for the application to the ultrasonicfluid measuring device that measures an average flow rate of the fluidflowing through the measuring pass.

1. An ultrasonic fluid measuring device, comprising: a measuring pass formed like a square cylinder whose cross section is a rectangle; an ultrasonic measuring portion in which a first ultrasonic transmitter-receiver and a second ultrasonic transmitter-receiver are provided to the measuring pass; and a plurality of pass partition plates contained in the measuring pass such that the pass partition plates are set in substantially parallel with an ultrasonic propagation path that connects the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver; whereby a plurality of flat passes are laminated/formed in the measuring pass by the pass partition plates, and wherein the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver are arranged with respect to respective flat passes such that the ultrasonic measuring portion measures a flow rate of a flat pass that is deviated from a center along a lamination direction.
 2. An ultrasonic fluid measuring device according to claim 1, wherein the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver are arranged to face to the flat pass that flows the fluid at an average flow rate out of the flat passes.
 3. An ultrasonic fluid measuring device according to claim 1, wherein the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver are arranged to extend over a plurality of flat passes that are adjacent mutually out of the flat passes.
 4. An ultrasonic fluid measuring device according to claim 1, wherein the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver are arranged to face to the flat passes except either of the flat passes, through which the fluid passes at a highest flow rate, and the flat passes, through which the fluid passes at a lowest flow rate.
 5. An ultrasonic fluid measuring device, comprising: a measuring pass formed like a square cylinder whose cross section is a rectangle; an ultrasonic measuring portion in which a first ultrasonic transmitter-receiver and a second ultrasonic transmitter-receiver are provided to the measuring pass; and a plurality of pass partition plates contained in the measuring pass such that the pass partition plates are set in substantially parallel with an ultrasonic propagation path that connects the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver; whereby a plurality of flat passes are laminated/formed in the measuring pass by the pass-partition plates, and wherein the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver are arranged to face to the flat passes except either of the flat passes, through which the fluid passes at a highest flow rate, and the flat passes, through which the fluid passes at a lowest flow rate.
 6. An ultrasonic fluid measuring device according to claim 1, wherein the ultrasonic propagation path that connects the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver has an angle to a flow of the measuring pass.
 7. An ultrasonic fluid measuring device according to claim 1, wherein the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver are provided to a side wall on a same side of the measuring pass, and a propagation time of an ultrasonic wave is measured by causing an ultrasonic wave to reflect on an opposing side wall surface of the measuring pass.
 8. An ultrasonic fluid measuring device according to claim 1, wherein the ultrasonic propagation path that connects the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver is set in substantially parallel with a flow in the measuring pass.
 9. An ultrasonic fluid measuring device according to claim 1, further comprising: a first ultrasonic measuring portion and a second ultrasonic measuring portion; wherein the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver of the first ultrasonic measuring portion are arranged such that the first ultrasonic measuring portion measures a flow rate of one flat pass that is deviated from a center along a lamination direction out of the flat passes, and the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver of the second ultrasonic measuring portion are arranged such that the second ultrasonic measuring portion measures a flow rate of other flat pass that is deviated from the center along the lamination direction.
 10. An ultrasonic fluid measuring device according to claim 9, wherein a first ultrasonic propagation path of the first ultrasonic measuring portion and a second ultrasonic propagation path of the second ultrasonic measuring portion are set in parallel when viewed along the lamination direction.
 11. An ultrasonic fluid measuring device according to claim 9, wherein a first ultrasonic propagation path of the first ultrasonic measuring portion and a second ultrasonic propagation path of the second ultrasonic measuring portion intersect with each other when viewed along the lamination direction.
 12. An ultrasonic fluid measuring device according to claim 5, wherein the ultrasonic propagation path that connects the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver has an angle to a flow of the measuring pass.
 13. An ultrasonic fluid measuring device according to claim 5, wherein the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver are provided to a side wall on a same side of the measuring pass, and a propagation time of an ultrasonic wave is measured by causing an ultrasonic wave to reflect on an opposing side wall surface of the measuring pass.
 14. An ultrasonic fluid measuring device according to claim 5, where in the ultrasonic propagation path that connects the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver is set in substantially parallel with a flow in the measuring pass.
 15. An ultrasonic fluid measuring device according to claim 5, further comprising: a first ultrasonic measuring portion and a second ultrasonic measuring portion; wherein the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver of the first ultrasonic measuring portion are arranged such that the first ultrasonic measuring portion measures a flow rate of one flat pass that is deviated from a center along a lamination direction out of the flat passes, and the first ultrasonic transmitter-receiver and the second ultrasonic transmitter-receiver of the second ultrasonic measuring portion are arranged such that the second ultrasonic measuring portion measures a flow rate of other flat pass that is deviated from the center along the lamination direction.
 16. An ultrasonic fluid measuring device according to claim 15, wherein a first ultrasonic propagation path of the first ultrasonic measuring portion and a second ultrasonic propagation path of the second ultrasonic measuring portion are set in parallel when viewed along the lamination direction.
 17. An ultrasonic fluid measuring device according to claim 15, wherein a first ultrasonic propagation path of the first ultrasonic measuring portion and a second ultrasonic propagation path of the second ultrasonic measuring portion intersect with each other when viewed along the lamination direction. 